Dual seal nozzle dam and alignment means therefor

Abstract

A nozzle dam for providing a fluid-tight seal across a primary fluid nozzle in the plenum of a nuclear steam generating vessel includes two fluid-impermeable seals, each comprising a circular three-section foldable seal plate covered with a flexible diaphragm and circumferentially encompassed by an inflatable seal member disposable in frictional sealing engagement with the inner surface of the nozzle. The two seal apparatuses are interconnected by a central tubular coupling coaxial with the nozzle and non-rotatably fixed to each seal, the coupling having a quick-disconnect feature operable from outside the nozzle dam. The coupling provides a conduit for inflation of one of the seals. The two seals are also interconnected by four post assemblies to maintain the seal plates parallel with each other, each post assembly including a cylindrical member pivotally movable between a release position and a supporting position, and provided with a slidable encompassing sleeve to lock it in the supporting position. Structure is provided for pressurizing the inter-seal space and monitoring the pressure in that space.

We claim: 
     
       1. A nozzle dam for preventing fluid flow through a primary fluid nozzle in the plenum of a nuclear steam generating vessel, wherein the nozzle has an inner surface and an axis, said nozzle damp comprising: first and second fluid-impermeable seal means disposable in sealing conditions axially spaced-apart within the nozzle and each seal means including an inflatable means, each of said seal means in the sealing condition thereof extending across and closing the nozzle and frictionally engageable with the inner surface thereof around the entire perimeter thereof in a sealing plane to form a fluid-tight seal, means for inflating said inflatable means, coupling means non-rotatably fixed to each of said seal means for interconnecting same in the sealing conditions thereof to maintain a predetermined axial spacing therebetween while inhibiting relative rotation thereof about the axis of the nozzle, said coupling means including disconnection means for separating said first and second seal means from each other, and support means spaced from said coupling means and rigidly interconnecting said first and second seal means for maintaining said sealing planes thereof substantially parallel to each other in a sealing orientation substantially perpendicular to the nozzle axis. 
     
     
       2. The nozzle dam of claim 1, wherein said coupling means is bolted to each of said first and second seal means. 
     
     
       3. The nozzle dam of claim 1 wherein said coupling means includes tubular means providing fluid communication with the inflatable means of one of said seal means. 
     
     
       4. The nozzle dam of claim 1, wherein each of said first and second seal means includes a plurality of sections foldably interconnected to facilitate insertion of the seal means into and removal of the seal means for the plenum of the nuclear steam generating vessel. 
     
     
       5. The nozzle dam of claim 1, and further including means for pressurizing the inter-seal space between said first and second seal means when they are disposed in their sealing conditions. 
     
     
       6. The nozzle dam of claim 1, and further including a polytetrafluoroethylene resin coating on exposed surfaces of each of said first and second seal means. 
     
     
       7. A nozzle dam for preventing fluid flow through a primary fluid nozzle in the plenum of a nuclear steam generating vessel, wherein the nozzle has an inner surface and an axis, said nozzle dam comprising: first and second fluid-impermeable seal means disposable in sealing conditions axially spaced-apart within the nozzle and each seal means including an inflatable means, each of said seal means in the sealing condition thereof extending across and closing the nozzle and frictionally engageable with the inner surface thereof around the entire perimeter thereof in a sealing plane to form a fluid-tight seal, means for inflating said inflatable means, and a plurality of support means rigidly interconnecting said first and second seal means at a plurality of spaced-apart locations thereon for maintaining said sealing planes there of substantially parallel to each other in a sealing orientation substantially perpendicular to the nozzle axis. 
     
     
       8. The nozzle dam claim 7, wherein said support means include a plurality of posts each fixedly secured to each of said first and second seal means. 
     
     
       9. The nozzle dam of claim 8, wherein said support means include four of said posts spaced apart in a substantially rectangular configuration centered about the nozzle axis. 
     
     
       10. The nozzle dam of claim 8, wherein each of said posts includes joint means for effecting separation of said first and second seal means from each other. 
     
     
       11. The nozzle dam of claim 7, wherein each of said first and second seal means includes a plurality of sections foldably interconnected, and each of said support means includes foldable sections, thereby to facilitate insertion of the seal means into and removal of the seal means from the plenum of the nuclear steam generating vessel. 
     
     
       12. The nozzle dam of claim 11, wherein said support means connects one of said sections on said first seal means with the corresponding section on said second seal means. 
     
     
       13. The nozzle dam of claim 7, and further including coupling means non-rotatably fixed to each of said seal means for interconnecting same in the sealing conditions thereof to maintain a predetermined axial spacing therebetween. 
     
     
       14. A nozzle dam for preventing fluid flow through a primary fluid nozzle in the plenum of a nuclear steam generating vessel, wherein the nozzle has an inner surface and an axis, said nozzle dam comprising: first and second fluid-impermeable seal means disposable in sealing conditions axially spaced-apart within the nozzle; and each seal means including an inflatable means each of said seal means in the sealing condition thereof extending across and closing the nozzle and frictionally engageable with the inner surface thereof around the entire perimeter thereof in a sealing plane to form a fluid-tight seal; means for inflating said inflatable means; and a plurality of support means rigidly interconnecting said first and second seal means respectively at a plurality of spaced-apart locations thereon for maintaining said sealing planes thereof substantially parallel to each other in a sealing orientation substantially perpendicular to the nozzle axis, each of said support means including retaining means fixedly secured to said first seal means, connecting means fixedly secured to said second seal means and movable between a support position engageable with said retaining means for retention thereby and a release position out of engagement with said retaining means, and lock means for locking said connecting means in the support position thereof. 
     
     
       15. The nozzle dam of claim 14, wherein each of said connecting means is pivotally movable between the support and release positions thereof. 
     
     
       16. The nozzle dam of claim 15, wherein each of said connecting means includes two cylindrical members arranged coaxially in the support position thereof, said lock means comprising a tubular sleeve coaxially surrounding one of said cylindrical members and slidable longitudinally thereof to a locking position encompassing both of said cylindrical members in the support position thereof for preventing movement thereof from said support position. 
     
     
       17. The nozzle dam of claim 15, wherein each of said retaining means comprises a generally U-shaped bracket dimensioned for receiving the distal end of the pivoting one of said cylindrical members in the support position thereof. 
     
     
       18. The nozzle dam of claim 14, including four of said support means.